Field of the Invention
This invention relates generally to the field of computer processors and software. More particularly, the invention relates to a method and apparatus for continued retirement during commit of a speculative region of code.
Description of the Related Art
In prior processor architectures, the reorder buffer (ROB) was forced to stall retirement when a region commit uop was the oldest until the memory system (MEU) was prepared to commit values altered in the region. This process caused the out-of-order speculation mechanism to get “backed up” while waiting for the MEU. That is, at the time the commit operation is at the head of the ROB and ready to retire, its retirement is held back, thus preventing the ROB from retiring and speculating deeper into code subsequent to the region. Delay in the retirement of the commit causes delay in the retirement of subsequent uops, which delays releasing resources causing yet other sources of delay.